Drag lever of a valve mechanism in an internal combustion engine

ABSTRACT

Disclosed is a drag lever ( 1 ) comprising two side walls ( 2, 3 ) which are connected together by a transversal bar ( 4 ) which is arranged on an end ( 6 ) of the lower side ( 5 ) thereof on an end ( 6 ) thereof on a head of a support element ( 9 ) by means of a dome-shaped cavity ( 7 ) on a head ( 8 ) of a support element ( 9 ). A clamp ( 10 ) is applied to the end ( 6 ) thereof. The clamp fixes the drag lever ( 1 ) to the head such that it can be displaced in a pivoting direction thereof. The clamp ( 10 ) is made of thin-walled wire material and extends essentially in a transversal manner in relation to the longitudinal axis of the drag lever ( 1 ) and is arranged on the lower side ( 5 ) of the transversal bar ( 4 ) by means of a central section ( 11 ) which is formed by webs ( 12, 13 ) which extend in a semi-circular manner in a part of the support element ( 9 ) which has a reduced diameter ( 14 ) and is located below said head ( 8 ). The clamp ( 10 ) continues on each outer surface ( 15, 16 ) of a corresponding side wall ( 2, 3 ) by means of two parallel projections ( 17   a,    17   b,    18   a,    18   b ) and the ends of said projections are snapped on an upper side ( 19, 20 ) of the respective side wall ( 2, 3 ) or on a bearing surface which is essentially parallel to the upper side ( 2, 3 ) such that at least more than half of the upper side ( 19, 20 ) or the bearing surface is covered.

FIELD OF THE INVENTION

The invention concerns a finger lever of a valve train of an internalcombustion engine, said finger lever comprising two side walls that areconnected to each other by a crossbeam that acts through an underside atone end on at least one gas exchange valve and is mounted at a furtherend through a concave cavity on a head of a support element, a clipthrough which the finger lever is fixed in position on said head fordisplacement in a direction of pivot being applied to said further end.

BACKGROUND OF THE INVENTION

A finger lever of the pre-cited type is disclosed in DE 35 00 524 C2that is considered to be generic. A leg of the clip disclosed in thisdocument extends in the direction of extension of the finger lever.During a pivoting motion of the finger lever generated by cam loading,this clip impedes the pivoting motion because bending work has to beperformed. This has a detrimental effect on the friction in the valvetrain.

OBJECTS OF THE INVENTION

It is an object of the invention to provide a finger lever of thepre-cited type in which the aforesaid drawbacks are eliminated.

This and other objects and advantages of the invention will becomeobvious from the following detailed description.

SUMMARY OF THE INVENTION

The invention achieves the above objects by the fact that the clip ismade of thin-walled wire material, extends substantially crosswise to alongitudinal axis of the finger lever and bears through a centralsection against the underside of the crossbeam, said central sectionbeing formed by two webs that extend on two side of a transverse planethat intersects the support element at a center point, said two webshaving a semi-circular shape and extending in a diameter reduction ofthe support element under the head of the support element, the clipbeing continued through two parallel extensions on an outer surface ofeach of said two side walls, ends of said extensions being snapped ontoone of an upper side of one of the side walls or onto a support surfacesubstantially parallel to said upper side so as to engage more than atleast one half of the upper side or of the support surface.

In this way, the aforesaid drawbacks are eliminated with simplemeasures. The finger lever can move freely in the direction of pivotand, at the same time, the wire-like clip constitutes a very economicand extremely light connecting means.

In place of the proposed wire material, the invention can also berealized with other materials having resilient properties such as, forinstance, thin-walled plastics and fiber-reinforced plastics etc.

Although the invention provides that the ends of the extensions on bothsides engage the upper sides of the side walls, it is also possible toimplement the invention with only one set of ends configured in thisway. The ends of the extensions are then snapped resiliently onto theupper side of the associated side wall. It is further provided by theinvention to make one end longer so that it extends on an inner surfaceof one of the side walls so as to ensure a particularly reliablepositional fixing.

To prevent a slipping of the clip of the invention in longitudinaldirection of the finger lever, the ends of the clip can extend by choiceat least on one upper surface in a depression. Alternatively, it is alsoproposed to arrange an elevation on at least one upper side, whichelevation is surrounded on both sides by the ends of the clip.

In a further advantageous embodiment of the invention, the ends of theclip are united on the associated upper side by choice. This may berealized on one upper side, but also on both upper sides, so that eithera clip open on one side or a completely closed clip is formed. In thelatter case, it may be necessary to use suitable joining measures toobtain a clip with a closed configuration in the region of its ends.

Due to the fact that the extensions on the side walls are spaced fromeach other at a distance that is smaller than a diameter of the diameterreduction, an excellent enclosing of the diameter reduction by thesemi-circular webs is guaranteed.

Finally, according to still another advantageous embodiment of theinvention, the finger lever has a generally U-shaped cross-section. Inplace of the U-shaped cross-section it is also possible to configure thefinger lever with a cross-section only similar in shape to a U or withan H-shaped cross-section. In combination with this feature, theinvention proposes to make the finger lever out of sheet metal. Furthermaterials will also occur to a person skilled in the art in thisconnection, for example, also plastics or a finger lever made bycasting. The scope of the invention, however, also includes the U-shapenot combined with sheet metal.

The invention will now be described more closely with reference to theappended drawing.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 shows a cross-section through a finger lever of the invention ina region of a support element,

FIG. 2 is a side view of the finger lever of FIG. 1 comprising a clip ofthe invention,

FIG. 3 shows the finger lever of FIG. 1 comprising a differentlyconfigured clip, and

FIG. 4 is a side view of the finger lever of FIG. 3.

DETAILED DESCRIPTION OF THE DRAWING

The figures disclose a finger lever 1 that is made in the present caseout of thin-walled sheet metal. This finger lever 1 is intended for usein a valve train of an internal combustion engine and comprises sidewalls 2, 3 that are connected to each other on their undersides by acrossbeam 4. Thus, as viewed in cross-section, the finger lever forms aU-profile. At its one end, not illustrated, the crossbeam 4 acts in liftdirection on at least one gas exchange valve. At a further end, thefinger lever 1 is mounted through a concave cavity 7 in the region of anunderside 5 for pivoting on a head 8 of a support element 9. Thissupport element 9 may be designed to operate hydraulically.

Through a clip 10 made preferably of thin-walled wire material andapplied in the region of the further end 6, the finger lever 1 isconnected to the support element 9 so as to be able to pivot freely inits direction of pivot. In this way, the finger lever 1 can be deliveredtogether with the support element 9 as an assembled unit to the enginemanufacturer and be completed in the cylinder head by the manufacturer.The clip 10, as an extremely cheap connecting element, at the same timeprevents the finger lever 1 from slipping off the head 8 of the supportelement 9 before and during mounting in the valve train and also whenthe internal combustion engine is fired.

As a person skilled in the art will readily see in the figures, the clip10 extends substantially crosswise to a longitudinal axis of the fingerlever 1. The clip 10 comprises a central section 11 bearing against anunderside 5 of the finger lever 1. This central section 11 comprises twowebs 12, 13 each of which extends in the form of a semi-circle in adiameter reduction 14 under the head 8 of the support element 9.Laterally, the ends (not referenced) of the webs 12, 13 are pulled viathe extensions 17 a, 17 b and 18 a, 18 b over a respective side wall 2,3 of the finger lever 1 onto a respective upper side 19, 20. The endsare snapped, so to speak, onto the upper sides 19, 20.

As disclosed in FIGS. 1, 2, the upper sides 19, 20, or at least oneupper side, can comprise an elevation 21 that is enclosed by the ends ofthe respective extensions 17 a, 17 b and 18 a, 18 b. In this way, aslipping of the clip 10 in the longitudinal direction of the fingerlever 1 is prevented. In the embodiment of FIG. 1, only one upper side19 comprises such an elevation 21. On the upper side 20, in contrast,the end of the clip 10 extends beyond the upper side 20 toward thecentral longitudinal plane of the finger lever 1 and has a closedconfiguration in this region. The ends on the upper side 19 are shown inan open state.

According to the illustration of FIG. 4, the ends (in the present case,those of the extensions 17 a, 17 b on the side wall 2) can also extendin a depression 22 on the upper side 19. This, too, is a method ofpreventing a slipping of the clip 10 in the longitudinal direction ofthe finger lever 1.

As disclosed in FIG. 3, it is, however, also possible, whereappropriate, to omit the elevation 21 and the depression 22, so that theends extend on upper sides 19, 20 having a smooth surface in thisregion.

FIG. 4 shows that the extensions 18 a, 18 b on the side wall 3 areunited and that the opposing ends have an open configuration.

1. A finger lever of a valve train of an internal combustion engine,said finger lever comprising two side walls that are connected to eachother by a crossbeam that acts through an underside at one end on atleast one gas exchange valve and is mounted at a further end through aconcave cavity on a head of a support element, a clip through which thefinger lever is fixed in position on said head for displacement in adirection of pivot being applied to said further end, wherein the clipis made of thin-walled wire material, extends substantially crosswise toa longitudinal axis of the finger lever and bears through a centralsection against the underside of the crossbeam, said central sectionbeing formed by two webs that extend on two sides of a transverse planethat intersects the support element at a center point, said two webshaving a semi-circular shape and extending in a diameter reduction ofthe support element under the head of the support element, the clipbeing continued through two parallel extensions on an outer surface ofeach of said two side walls, ends of said extensions being snapped ontoone of an upper side of one of the side walls or onto a support surfacesubstantially parallel to said upper side so as to engage more than atleast one half of the upper side or of the support surface.
 2. A fingerlever of claim 1, wherein at least one side wall comprises on the upperside, an elevation that is surrounded by at least one end of at leastone of the extensions at least on one side.
 3. A finger lever of claim1, wherein at least one side wall comprises on the upper side, adepression in which the ends of the extensions on said at least one sidewall are guided.
 4. A finger lever of claim 1, wherein at least one sidewall comprises on the upper side, two elevations between which the endsof the extensions on said at least one side wall are guided.
 5. A fingerlever of claim 1, wherein the extensions on the side walls are spacedfrom each other at a distance that is smaller than a diameter of thediameter reduction.
 6. A finger lever of claim 1, wherein the ends ofthe extensions on at least one upper side are united and the ends of theextensions on the other upper side, in case of a united configurationonly on one upper side, are open.
 7. A finger lever on claim 1, whereinthe ends of the extensions on at least one upper side extend completelyover this upper side and are snapped through an end portion behind aninner surface of the side wall.
 8. A finger lever of claim 1, whereinthe finger lever has a generally U-shaped cross-section and is made ofsheet metal.